1. Field of the Invention
This invention relates to thermal containers, and in particular to a lidded cold cup.
2. Background of the Invention
Canned drinks have become the standard for individual serving sized drinks. Today's consumer can purchase a wide variety of drinks, ranging from soft drinks and fruit juices to alcoholic beverages, in standard sized, 12 oz. cans. These canned drinks may be procured individually from vending machines, or from merchants, generally in 6-pack, 12-pack or 24 unit case packages.
The cans in which these beverages are sold are generally made of thin aluminum or other appropriate metal. This type of thin metal generally conducts heat well, and so it becomes a problem to maintain the beverage at an appropriate temperature (generally chilled). This problem becomes especially acute where the beverage is being consumed in a hot climate. Absent some kind of insulation, it is difficult to finish the drink before it warms to a distastefully high temperature.
3. Existing Designs
A number of designs have been proposed which involve wrapping a layer of insulation around a can in order to insulate its contents from the outside temperature. A number of patents have been granted for this type of design, including U.S. Pat. No. 5,467,891 to Perry, U.S. Pat. No. 5,147,067 to Effertz, and U.S. Pat. No. 4,268,567 to Harmony. These designs all provided insulation to the sides of a cylindrical can, but not to its top.
There are a number of problems associated with not providing a top to a can insulation device. One problem is lack of insulation. A can loses a substantial amount of its interior temperature through its top. Applicant has determined that an insulated can top can keep the contents of a beverage can cold approximately 40% longer than a can whose top is uninsulated.
Another problem associated with not providing a can top is spillage. Where a tightly fitting can top is provided, spillage can be reduced and even eliminated completely if the can tips over. Still another problem associated with not providing a can top is bug or other foreign matter invasion. Occasionally a bug will crawl or fly into a beverage can, and then inadvertently end up in the consumer's mouth. This situation creates a sanitary hazard, and in the case of a poisonous bug, a safety hazard.
A number of patents have been granted for can insulators which incorporate caps. U.S. Pat. No. 5,058,757 was granted Proa for a can cooler with a retractable umbrella. While this design provided shade for the can for certain sun angles, the umbrella prevented neither spills nor bug incursion.
U.S. Pat. Nos. 4,561,563, 4,872,577 and 5,564,583 were granted Woods, Smith and Kelley et al. respectively. While these designs provided a removable can cooler top, they suffered from complexity of design, and thus were expensive. In addition, most of these designs (except for '563) made no provision for one-handed operation. Thus these designs (except for '563) were cumbersome to open and close. The '563 design was complex, and involved a pair of opposing doors spring-loaded into the closed position. This design suffered from the drawbacks of complexity and expense, and appeared difficult to clean.
U.S. Pat. No. 5,048,734 was granted Long for a cooler incorporating an insulated cover flap hingedly connected to a cylindrical body which could be retained in a closed position by means of a Velcro strip. While this design provided an insulated cover which could fit tightly over a can top, it was cumbersome to operate because to open the top, the consumer had to first peel the Velcro free of the cylindrical body, and then open the top, and hold it open while the beverage was being consumed, then close the top and press the Velcro strip down to hold the top closed. Thus, two-handed operation was required throughout the top opening, drinking, and the top closing steps, resulting in inconvenience and cumbersomeness.
Stuber et al. received U.S. Pat. No. 4,927,047 for a beverage insulator which incorporated a side handle, and a top held closed by means of a rubber band. The Stuber design was apparently made of rigid material, and thus did not seal tightly around the top of a can contained in it. The top incorporated a thumb-lever. Thus, the '047 design provided a top which could be opened single-handedly by an individual whose fingers were holding the container by its handle, and whose thumb was in contact with the thumb lever.
This design suffered from a number of problems. If the rubber band broke, not only would the top not stay closed, but it would fall off the insulator completely. In areas of high sunlight, where one would typically use a can insulator, ultraviolet radiation severely limits the life of a rubber band due to solar embrittlement. Thus the reliability of this design is severely compromised by its rubber band weak link. And where the rubber band failed at an inopportune time, the top could be irretrievable lost.
Another problem associated with the '047 design is the lack of a tight seal between a beverage container contained in it and the insulator top. If the insulator were to tip over, liquid contained in the beverage container would not be contained, and would spill out through the crack between the top and the insulator.
Another drawback associated with the '047 design is its top thumb lever design. In order to open the top, the consumer must introduce at least one or two fingers through the handle, and then use his thumb on the top thumb lever to open the top. If the '047 design lacked a handle, the top opening scheme wouldn't work. Thus in order to function, this design required an insulator handle, thus contributing to its complexity and expense.